System of electrical distribution.



J. L. JOHNSON. SYSTEM 01? ELEOTRIOAL DISTRIBUTION. APPLICATION FILED SEPT.16, 1910.

,-1,132,478. Patented Mar. 16, 1915.

, VAR/ABLE LO/i'D la 2: 2a

i To all whomit may concern:

Unirrnn STATES PATENT curios.

JOHN L. JOHNSON, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 ALLIS-CHALMEBS MANUFACTURING COMPANY, A CDRPORATION OF DELAWARE.

I SYSTEM or uncritical DISTRIBUTION.

Specification of Letters'latent.

' Application filed September 16, 1910. Serial No. 582,302.

Be it known that I, JOHN L. JoHNsoN, a citizen of the United States, residing at lililwaukee, in the county of Milwaukee and Stateof Wisconsin, have invented certain new and useful Improvements in Systems of Electrical Distribution, of which the following is a full, clear, and'eizacitspecifica-v tlon- I i l My invention relates to systemsi of electrical distribution. a h

In many electrical systems, there is a fluctuation of the load between very Wide vlimits, the upper limit often exceeding the 15' capacity of t e generator supplying the sys,

tem. In systems of this sort it has been proposed to connect across the line ad nameelectric machine whose rotating mom or has large inertia, which machine acts as a motor to store upkinetic energy when the load on the line is light and as a generator driven by such stored energy when the load on the line is heavy.

It is the object of my. resent invention to obtain in a system of t is sort a simple and reliable arrangement by which the storing and giving up of the kinetic energy may be more readily andiaccurately controlled.

In attaining this object I'employ means whereby the relation between the speed of the dynamo-electric unit and the speed at which the fiy-wheel is rotating isvaried, preferably under the control of the load on the circuit. The invention is preferably used in connection with alternating currentsystems, though its use is not limited tovsuch systems.

' Specifically-considered, the invention comprises a dynamo-electric machine and sets of gearing of different ratiosfor connecting a fly-wheel to" said dynamo-electric machine.

The speed at which the fiy-wheel normally.

' runs is that resulting from the operation of that set of gearing which if drivenby the dynamo-electric machine would give the fly wheel its maximum speed, and one or' the I other 01 the sets of gearing is rendered op er'ative according as the load on the circuit is, light 5 or heavy. When the load. is light the gearing which if driven by the dynamo.- electr'ic machine would; ive' the flywheel the maximum speed, is e ective, and the dynamo-electric machine acts as .a motor to store upkinetic energy inthe fl'y-wheel.

When the load is heavy, the gearing which if matic'ally controlled.

driven by the dynamo-electric machine wheel is given up to drive the dynamo-electric machine as a generator to cause -it to supply energy to the circuit. which the dynamo-electric machine su plies energy to the line may be adjustab e, ut preferably the whole operation is auto- The various novel features of my invention will be described in the specification and particularly set forth in the claims.

The single figure of the drawin shows diagrammatically one embodiment o my inventlon. -The generator 10 supplies the distribution. circuit 1112---l3 on which there is a load which fluctuates quite rapidly within wide limits. The load may be of any character. cable to those cases where the variable load is a power load, consisting, for instance, of one or more rolling mill motors.- The generator as here shown is a three phase generator, but my invention in its broader aspects is not limited to three phase systems. Across the circuit l1-12 a dynamo-electric machine whoserotatingmember has large inertia, as by being geared to a fly-wheel 15. This dynamo-electric machine is arranged to act as a motor to store up energy in the fly-wheel when the load on the circuit 11--12-13 is light and as a generator driven by the energy of the fly-wheel to supply current to the circuit 1l--12-13 when he load on such circuit is' heavy. The arrangement for controlling the consumption and production of energy by the dynamo electric machine and fly-wheel is the essence of my present invention.

In the arrangement shown the dynamoelectric machine consists of an induction motor 14 of the squirrel cage type, having a single synchronous speed. Mounted upon the shaft of the motor 14 are two spur gears 16 and 17, cooperating with two gears 18 and l9 respectively mounted loosel upon a can ter shait 20 to which the y-wheel 1e secured? Keyedto the shaft-20 is a magnetic clutch member 21 having two windings 22 and 23 which attract the armatures 24 and 25 respectively secured to the gears, 18 and 19 respectively. The ma netic c utch -21 is energized by any suitab e source of The rate at The invention is especially appli- 13 is connected 7 1 sired manner. When the load on the circuit 1112-13 is below a predetermined value, the switch 27 is in the position shown and the. winding 22 is energized This attracts the armature 24 which is secured to the gear 18 and forms a driving connection between ithe gear 18 and the shaft 20. The gears 16 and 17 secured to the shaft of the motor 14 are of different diameters, the gear 16 which meshes with the gear 18 being of larger diameter than the-gear 17. If the driving connection is made through the gear 16 to the shaft of the fly-wheel'15 the speed ratio between the speed of the motor 14 and thefly-wheel 15 will be greater than if the fly-wheel were driven through the gear 17. Withthe clutch in the position shown, the

fly-wheel is rotating at its maximum speed.

When the load on the circuit increases and the current supplied by the generator 10 excoeds the value for. which the switch 27 is set, said switch is moved to the left and the clutch winding 23 becomes. energized and forms a driving connection between the gear.

' 17 and the shaft 20 of the fiy-wheel 15. Be-

fore this change in the driving connections,

the fly-wheel is rotating at maximum speed and the speed ratio between the motor and the fly-wheel is at its maximum. After this change the speed ratio between the motor and the fly-wheel'islowered, and, due to the large inertia of the -fly-wheel 15, the speed of the motor 14 is increased. In consequence of this change of speed ratio the ac.- tual speed of the motor 14 is increased above its synchronous speed and the motor. 14,

driven by the. energy in the fly-wheel 15 supplies energy to the circuit '11-12--13.

Assoon as the load on the circuit 11-12-13- drops and the current supplied by'the generator 10 becomes less than that for which the switch 27 is set, said switch is allowed to. move back to its original position and to deenergize thewinding 23 and to energize the winding 22. The motor is nowallowed to run at its synchronous speed and to accelerate'the fly-wheel. Two resistances 31 l and 32 are included in'the circuit of the windings 22 and 23 respectively. These resistances are controlled y theswitch 27 and allow a certain amount of slipjfin'the driving connection between the motor 14- and the flyeW-heel 15, the amount of slip being regulated by the amount of resistance in circuit.

If the load on the circuit 11-12-l3 is slightly above the value for which the spring 28 is set the switch 27 allows a large part of the resistance 32 to remain in the circuit of the winding 23 and the slip between the driving connection of the motor 14 and the fly-wheel 15 is very large. This results in only a slight increase in the speedof the motor 14 above synchronism. If the load on the circuit 11 1213 is large all of the resistance 32 is cut out of circuit. and the slip of the driving connection is greatly decreased. This results in the motor 14 being driven at its maximum speed above synchronism and in a. great deal of current being supplied to the line.

One specific embodiment of my invention has been described, but the invention is not limited to it. Many other arrangements may be used for driving the fiy-wheel and for varying the relative speeds between the motor and the fiy-wheel. Other arrangements may also be used for regulating the amount of current returned to the line. I aim in my claims to cover all such modifications which do not depart from the spirit and scope of my invention.

What I claim as new is:

1 In combination, .a generator, avariable load circuit supplied thereby, a dynamo- -electric machine connected across said circuit, a'fly-wheel, and a device for connecting said fly-wheel to said dynamo-electric machine and for changing the speed ratio of sa1d. fly-wheel to .said dynamo-electric inachinewhen the load on said circuit varies.

2. In. combination, a generator, a variable load circuit-supplied thereby, a dynamo electric machine connected across said circuit, a fly-wheel, and a device for connecting said fly-wheel to said dynamo-electric machineand for changing the speed ratio of said fiy-wheel to said dynamo-electric machine when the load on said circuit fall's uelow a predetermined value.

. 3.- In-combination, a generator, an electric circuit supplied thereby'and carrying a variable load, a dynamo-electric machine connected across said 'bircuit, a fly-wheel, and a device for connectln said. fly-wheel to said dynamo-electricmac no, and for lowering the speed ratio of said fly-wheel to said dynamo-electric machine when the load on said circuit is above a predetermined value.

4. In combination, a generator, a variable load circuit supplied thereby, a dynamoelectric machine connected across said cirv cuit, a fly-wheel, and a device for connecting said fly-wheel to said dynamo-electric machine, and for increasing the speed ratio of said fly-wheel to said ,dynamo-electric-machine when the load on said circuit falls below a predetermined value.

5. In combination, .a generator, a circuit supplied thereby, adynamo-electric machine connected across said circuit, a fly-wheel, and a device for connecting said fly-wheel to said dynamo-electric machine and for varying the speed ratio of said fly-wheel to said dynamo-electric machine, and means responsive to the load ling said device.

6. In combination, an alternating current circuit, an induction motor connected across said circuit, the rotating member of said motor being connected to a member of great inertia, and means responsive to the load on said circuit for raising the actual speed of said motor relatively to the synchronous speed thereof when the load on the circuit rises above a predetermined value.

7. In combination, an alternating current generator, an alternating current circuit supplied thereby, an induction motor connected across said circuit a member of great inertia connected to the rotating member of said motor, and means responsive to the current supplied by said generator for varying the speed of the motor relatively to its synchronous speed in the same sense as the current supplied by said generator varies relatively to a predetermined value.

8. In combination, an alternating current circuit, an induction motor connected across said circuit, a member of comparatively great inertia connected to the rotor oi said motor, and means for varying the actual speed of said motor between an approximately synchronous value and a value in excess of synchronism.

9. In combination, a generator, an electric circuit supplied thereby and carrying a variable load, an induction motor connected across said circuit, a fly-wheel, high and low speed transmissions for connecting said inotor to said fly-wheel, a magnetic clutch for rendering either of said transmissions operv ative, and means controlled by the load on said circuit for operating said clutch.

10. In combination, a enerator, an elec-' tric circuit supplied there y and carrying a variable load, a dynamo-electric machine on said circuit for control-.

connected across said circuit, a fiy-wheel, means includin a magnetic clutch and responsive to the oad on said circuit for causing Said dynamo-electric machine to act as a motor to store up energy in said fly-wheel when the load on said circuit is light, and for causing said fly-wheel to drive said dynamo-electric machine as a generator to return energy to the circuit in an amount varying with the value of the load above normal when the load on said circuit is heavy.

11. In combination, a generator, an electric circuit-supplied thereby and carrying a variable load, an induction motor connected across said circuit, a fly-wheel, high and low speed transmissions for connecting said motor to said fly-wheel, a magnetic clutch for rendering either of said transmissions operative, and means controlled by the load on said circuit for gradually rendering said clutch completely eflective.

12. In combination, an alternating current circuit, an induction motor connected across said circuit, a member of comparatively great inertia connected to the rotating member of said motor, and means responsive to the load on said circuit for changing the actual speed of said motor relatively to the synchronous speed thereof when the load on the circuit changes.

13. In combination, an alternating current circuit, an induction motor connected across saidcircuit, a member of comparatively great inertia connected to the rotating member of said motor, and means responsive to the load on said circuit for changing the actual speed of said motor relatively to the synchronous speed thereof when the load on said circuit rises above a predetermined value.

Milwaukee, Wis, Sept. 9, 1910.

In testimony whereofI afiix my signature in the presence of two witnesses.

JOHN L. JOHNSON.

Witnesses:

G. B. SGHLEY, GHAs. L. BYRON. 

